Greenwood, who played his college ball at Albion, had surgery to repair a sports hernia prior to the start of training camp and has been on the physically unable to perform list. This week is the first he is eligible to begin practicing.

"He's been working with our trainers and everything else and I would expect him to get back to practice," coach Jim Schwartz said on Monday.

Once Greenwood returns to practice, the team has 21 days to decide whether to add him to the active roster, cut him, or place him on injured reserve.

"Yeah, you see how he is before you (make a decision)," Schwartz said. "Once you activate him (to start practicing), you have a couple weeks before you activate him to the 53, so we'll just see what he looks like and how he's doing."

When the Lions selected Greenwood in the fifth round of the draft, general manager Martin Mayhew indicated the small school sensation was a developmental project.

Greenwood has ideal size and speed for the cornerback position. He's 6-foot-1, weighs 195 pounds and ran a 4.42 40-yard dash at the University of Michigan's pro day.